Hello Eleanor,You need to go into the phone's main menu, tools and then speed dial. Select the key you wish to use for speed dial with left or right arrow. Go into options, and if you haven't set any up you will hear "assign". If the number is in your contacts list select it. You can only assign keys 2 to 9 for speed dialling, key 1 is reserved for voicemail.
Hope this helps. Best wishes, Clive Pallett